jominy test - ammattikorkeakoulut

JOMINY TEST

Design & Manufacturing Plan of a Jominy Testing Device

Bachelor's thesis

Mechanical Engineering & Production technology

Riihimäki 2012

James Alison Orivri

ABSTRACT

Unit

Name of degree programme

Option

Author James Alison Orivri Year 2012

Jominy Test Design & Manufacturing Plan of a Jominy Testing Device

ABSTRACT

The purpose of this work is to make one of the many heat treatments de-

vices- Jominy end quenching testing machine of manufacturing processes.

In the process, cases and related topics are going to be considered; neces-

sary information to give the reader in-depth knowledge and understanding

into the issue will be elaborated.

The idea of this project is to design a Jominy end quench testing machine

which will be safe, ease to use, simple to understand, able to be managed

by one person if needed, have a clear view of the heat treatment process

while in operation, economic, have a low maintenance cost, durable, meets

all CE standards and will be suitable for manufacturing. Materials for this

thesis was sourced via several means including Finnish Standards Asso-

ciation SFS, world wide web, books and materials on heat treatments as

well as one on one conversations with experts in this field. At the end of

this project, the reader should have a good insight and understanding of

the idea behind heat treatments and Jominy end quenching test.

A major part of this work involved the project drawings using 3D software

of choice-Pro Engineer wildfire. This required a good knowledge of the

programme and technical drawings as a manual of a step by step process

to produce the said machine by means of the drawings in 2D and 3D for-

mats will be made available. It should also be stated that while this is a

project with customized dimensions, design and style, I examined some

existing machines and considered their advantages, limitations and the

simplest way to apply concepts which are cost efficient to my design.

Keywords Jominy test, design, temperature, hardenability, hardness, tempering.

Pages 28pp. + Appendices 8pp.

CONTENTS

INTRODUCTION ....................................................................................................... 1 1

Heat treatments-the origin of jominy test ............................................................ 1 1.1

Why heat treatment and what can be heat treated ............................................... 1 1.2

1.2.1 Softening .................................................................................................. 1 1.2.2 Hardening ................................................................................................ 2 1.2.3 Material Modification .............................................................................. 2

Basic concept of heat treatment and the procedure ............................................. 2 1.3

Types of heat treatment ...................................................................................... 4 1.4

1.4.1 Spheroidizing: .......................................................................................... 4 1.4.2 Normalising ............................................................................................. 4 1.4.3 Hardening (Quench hardening) ............................................................... 4

1.4.4 Austempering .......................................................................................... 5

1.4.5 Full annealing .......................................................................................... 5 1.4.6 Case, Surface hardening and Tempering ................................................. 6

1.4.7 Tenifer treatment ..................................................................................... 6

JOMINY END QUENCHING TEST IN HEAT TREATMENTS ............................ 7 2

The concept of Jominy test.................................................................................. 7 2.1

Connection of jominy test to real the world and working materials ................... 7 2.2

Simulation and Practical based approach of jominy test in heat treatments ....... 7 2.3

Hardenability In Jominy Test .............................................................................. 8 2.4

Advantages & disadvantages of Jominy Test ................................................... 10 2.5

Testing Procedure .............................................................................................. 10 2.6

Uses of hardenability values ............................................................................. 13 2.7

Effects of alloying and microstructure .............................................................. 13 2.8

2.8.1 Carbon ................................................................................................... 14 2.8.2 Other alloying elements ......................................................................... 15

2.8.3 Boron ..................................................................................................... 15 Grain size........................................................................................................... 15 2.9

How to produce the result ................................................................................. 16 2.10

2.10.1 Contourplots .......................................................................................... 16

DESIGN PLAN OF JOMINY TESTING MACHINE ............................................. 18 3

Basic concept of the design ............................................................................... 18 3.1

3.1.1 Design standardization .......................................................................... 18 3.1.2 Why design a new machine & Problems of existing machine .............. 18 3.1.3 Possible changes & why this was considered the better design over

possible options ...................................................................................................... 19

3.1.4 Features of the new design: ................................................................... 20 Parts drawing and design: ................................................................................. 21 3.2

3.2.1 Welding drawing and design: ................................................................ 21 3.2.2 2-D Drawings: ....................................................................................... 22 3.2.3 Parts with high level of precision: ......................................................... 22 3.2.4 Assembly drawing and design: .............................................................. 24

MANUFACTURING OF JOMINY TESTING MACHINE POSSIBLE PLAN. ..... 25 4

1.1 Cost &Economic approach to design and manufacture .................................... 25 1.1.1 Safety & Maintenance of new manufactured machine ....................... 25

CONCLUSION ......................................................................................................... 26 5

SOURCES ...................................................................................................................... 27

Appendix 1: 3D models of the proposed design


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INTRODUCTION 1

Heat treatments-the origin of jominy test 1.1

Heat Treatment is the controlled heating and cooling of metals to alter their physical,

chemical or mechanical properties without changing the product shape. Heat treatment

is sometimes done inadvertently due to manufacturing processes that either heat or cool

the metal such as welding or forming (Wikipedia, 2012).

The general purposes of a heat treatment are to improve the flexibility of soft tissues,

remove toxic substance and to uniform the material composition and general quality of

a metal piece. Jominy test is one of the techniques used to determine the outcome of a

heat treatment method.

Why heat treatment and what can be heat treated 1.2

Heat treatment is often associated with increasing the strength of material, but it can

also be used to alter certain manufacturing objectives such as improve machining, im-

prove formability and restore ductility after a cold working operation. Thus it is a manu-

facturing process that can not only help other manufacturing process, but can also im-

prove product performance by increasing strength or other desirable characteristics.

Steels are particularly suitable for heat treatment, since they respond well to heat treat-

ment and the commercial use of steels exceeds that of any other material. Steels are heat

treated for one of the following reasons:

1. Softening

2. Hardening

3. Material Modification.

1.2.1 Softening

Softening is done to reduce strength or hardness, remove residual stresses, improve

toughness, restore ductility, refine grain size or change the electromagnetic properties of

the steel restoring ductility or removing residual stresses is a necessary operation when

a large amount of cold working is to be performed, such as in a cold-rolling operation or

wiredrawing.


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1.2.2 Hardening

Hardening of steels is done to increase the strength and wear properties. One of the pre-

requisites for hardening is sufficient carbon and alloy content. If there is sufficient Car-

bon content then the steel can be directly hardened. Otherwise the surface of the part has

to be Carbon enriched using some diffusion treatment hardening techniques.

1.2.3 Material Modification

Heat treatment is used to modify properties of materials in addition to hardening and

softening. These processes modify the behaviour of the steels in a beneficial manner to

maximize service life e.g., stress relieving, or strength properties example cryogenic

treatment, or some other desirable properties like spring aging.

Basic concept of heat treatment and the procedure 1.3

Steels are iron-carbon alloys whose characteristics can be influenced by changing the

chemical composition (C-content and by adding alloying elements) as well as through

heat treatment. This means that there is a large number of constructional steels which

fulfil all requirements. In order to understand the various heat treatments, it is necessary

to be familiar with the processes which take place in constructional steel during heating

and cooling.

The constitutional diagram iron-carbon forms the initial basis for heat treatment. It

shows the microstructural constituents and amounts present in a condition of equilibri-

um. It can be seen from the constitutional diagram that austenite and, in hypereutectoid

steels, austenite and cementite are present at temperatures above the GSK line. Very

slow cooling leads to conditions of equilibrium at room temperature and causes the aus-

tenite to convert into other types of microstructure.

Steels with less than 0.8 % carbon content segregate ferrite out of the austenite during

cooling and the remaining austenite disintegrates at under 723°C into perlite. With a

carbon content of 0.8 %, perlite only forms as a mixture of ferrite and cementite. In

steels with over 0.8 % carbon content, perlite and cementite form, whereby the second-

ary cementite is segregated out at the grain boundaries. By adding alloying elements,

the transformation temperatures and lines of equilibrium can be changed and the for-

mation of carbides influenced. (James Marrow, Manchester Materials Science Centre,

UMIST, Manchester, UK , 2001)


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FIGURE 1 Constitutional diagram iron-carbon


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Types of heat treatment 1.4

Heat treatment can be divided into two groups- superficial and deep. Superficial heat

treatments apply heat to the outside of the body. Deep heat treatment directs heat toward

specific inner tissues through ultrasound or by electric current. Heat treatments are ben-

eficial prior to exercise, providing a warm-up effect to the soft tissues involved and the

two groups are further divided into various types as listed below:

1.4.1 Spheroidizing:

Spheroidizing also called soft annealing, is carried out at a temperature of just under

Ac1*, sometimes also over Ac1 or by fluctuating around Ac1 with subsequent slow

cooling to achieve a soft condition.

Through this heat treatment, the cementite lamination of the perlite is transformed to a

spherical form - known as granular cementite. This type of microstructure provides the

best workability for steels with a C-content of more than approx. 0.5%. Granular ce-

mentite provides the condition for best workability for any type of cold working e.g. for

cold-heading, drawing, or cold extrusion. (AG, 2011a.).

1.4.2 Normalising

When normalising, the steel is heated to a temperature (approx. 20°C to 50°C) above

the upper transformation point Ac3*, for hypereutectoid steels above Ac1, and is then

cooled in static air. It is used to achieve an even, fine-grained microstructure. The high-

er the heating and cooling speeds, the finer the grains in the microstructure become,

providing that the transformation during cooling takes place in the perlite stage.

Through normalising, an uneven and coarse grained microstructure which has come

about during hot forming can be eliminated. (Denis S., 1984), (Denis S., 1984)

1.4.3 Hardening (Quench hardening)

The term hardening is used to describe cooling from a temperature above the transfor-

mation points A3 or A1 at such a speed that on the surface or throughout, there is a sig-

nificant increase in hardness, generally through the formation of martensite. The heating

must be carried out to a temperature above the transformation points Ac1 or Ac3 and

the cooling from a temperature above the transformation points Ac1 or Ac3.

The aim of the hardening is to achieve as high a level of hardness as possible in the

work piece. The hardness reached depends on the carbon content of the steel and its

hardenability whereby the dimensions of the work piece and conditions during heat


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treatment also play a role. In order to carry out optimum hardening, it is necessary to

adhere to the temperatures given and times for holding these as well as to correctly se-

lect and handle the hardening medium. The most suitable hardening values are to be

achieved through hardening during the martensite phase.

The quenching media are usually water, oil or air, whereby the application depends on

the critical cooling speed of the steel. In each case, the mildest quenching medium pos-

sible is used for each particular case, in order to keep the risk of tearing and distortion to

a minimum.

- A1 point refers to the eutectoid transformation point (723°), where one solid

transforms into two different solids.

- A3 point is the (a-g )-iron-transformation

- Ac1, Ac3 point is the arresting point on the heating curve at A1- a/o. A3-

transformation (that is the temperature at which that transformation of ferrite

to austenite is completed during heating).

- (c means chauffage, meaning heat)

- Ar1,Ar3 point refers to the arresting point on the cooling curve at A1- a/o.

A3- transformation

- (r means refroidissement, meaning cooling) (AG, 2011a.).

1.4.4 Austempering

The term austempering is used to describe the quenching of a workpiece from the hard-

ening temperature in salt and metal baths of a temperature lower than is required for the

formation of perlite but higher than for the formation of martensite. This is maintained

until the transformation to bainite has ended and there is subsequent cooling as desired

to room temperature. Isothermal transformation into bainite of this type results in very

low distortion levels and excellent toughness properties and tempering is not required.

(AG, 2011a)

1.4.5 Full annealing

The term full annealing is used to describe annealing at a temperature above the upper

transformation point Ac3 with cooling as required to suit the purpose and achieve a

coarser grain.

As a result of the coarse grains, good workability is obtained, above all, in steels with a

low carbon content and a highly ferritic-perlitic microstructure. This improvement is

based on the fact that the work piece with coarse grains has a low degree of toughness

meaning that a slightly brittle swarf occurs on it and this, in turn, leads to a reduction in

wear when cutting (AG, 2011a.), (efunda, 2011) (Denis S., 1984).


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1.4.6 Case, Surface hardening and Tempering

The term case hardening is used to describe hardening after previous carburization and,

possibly, simultaneously increasing the nitrogen content of the surface.

It is used in cases where besides high core toughness, a work piece also needs to have a

hard surface which is resistant to wear. Furthermore, through case hardening, the fatigue

strength is increased at the edges due to inherent stresses. Steels used for this have low

C contents and, depending on the desired core toughness, may be alloyed. For case

hardening, depending on the material and shape and size of the work pieces, various

types of treatment can be considered which in turn yields the desired result.

While surface hardening is used to describe heating of work pieces which are confined

to the surface during which the core remains below the hardening temperature and is not

hardened at all during quenching. This heating confined to the surface is achieved by

gas flames (flame hardening) or inductive heating. As a result of these types of heating,

under corresponding conditions, it is possible to achieve heating to hardening tempera-

ture throughout but then these types of heating can no longer be called surface harden-

ing. Special types of surface hardening are case hardening and nitride hardening. Imme-

diately after hardening, the parts are treated at approx. 200°C to relieve stresses.

Tempering on the other hand is used to describe heat treatment to achieve high levels of

toughness with a particular tensile strength by hardening and subsequently annealing,

normally at high temperatures. The mechanical properties of a tempered steel, in partic-

ular its toughness, depend to a large degree on the care taken during the tempering

treatment. (Denis S., 1984)

1.4.7 Tenifer treatment

Tenifer treatment is a salt bath process especially developed from soft nitriding. As a

nitrogen carrier, a KCN/KCNO salt bath with air cooling is used. The parts are treated

at approximate 570°C for between 30 and 120 min. and are then cooled in water or air,

depending on the material and shape.

(AG, 2011a. (Westmoreland Mechanical Testing & Research, 2012))

.


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JOMINY END QUENCHING TEST IN HEAT TREATMENTS 2

The concept of Jominy test 2.1

The Jominy end-quench test is the measure of the hardenability of steel, which is a

measure of the capacity of the steel to harden in depth under a given set of conditions.

(Westmoreland Mechanical Testing & Research, 2012).

Knowledge about the hardenability of steels is necessary to select the appropriate com-

bination of alloy steel and heat treatment to minimize thermal stresses and distortion in

manufacturing components of different sizes. The Jominy end-quench test is the stand-

ard method for measuring the hardenability of steels. This describes the ability of the

steel to be hardened in depth by quenching. Hardenability depends on the chemical

composition of the steel and also be can affected by prior processing conditions, such as

the austenitizing temperature. It not only is necessary to understand the basic infor-

mation provided from the test, but also to understand how the information obtained

from the Jominy test can be used to understand the effects of alloying in steels and the

steel microstructure. (Industrial heating, 2012.).

Connection of jominy test to real the world and working materials 2.2

Heat treatment is an indispensable step in the manufacture of steel products, as mechan-

ical properties such as hardness, static, and dynamic strength and toughness are selec-

tively controlled by deliberate manipulation of the chemical and metallurgical structure

of a component. However, apart from the desired effects, the heat treatment process can

be accompanied by unwanted effects such as component distortion, high material hard-

ness, low material strength, a lack of toughness which can lead to crack formation and

inadequate hardness depth, which can lead to fatigue failure. Therefore, success or fail-

ure of heat treatment not only affects manufacturing costs but also determines product

quality and reliability. Heat treatment must therefore be taken into account during de-

velopment and design, and it has to be controlled in the manufacturing process. Part

designers and heat treatment practitioners are looking for process feasibility, a specific

microstructure fitting to the in-service requirements, minimum part distortion, and

proper distribution of residual stresses.

Due to this pending need, jominy test in introduced to cub these issues.

Simulation and Practical based approach of jominy test in heat treatments 2.3

Jominy test of heat treatments can be achieved in two ways- the simulation based design

or the practical approach. Information will give in details on the practical approach as

that is the idea behind this project, however is expedient to shed some light on the simu-

lation based design approach. SYSWELD is one of the tools possible for such approach.


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It is finite element software which permits for not only jominy tests to be carried out but

all other heat treatment processes to be achieved taking all significant physical effects

into account. Thus, the part designer/heat treatment practitioner can have a deliberate

influence on minimizing manufacturing costs and optimizing product reliability and

quality. The Jominy test is implemented as a predefined, ready-to-run simulation project

in SYSWELD. The user defines the chemical composition of the steel, and the compu-

tation of the Jominy test is done automatically.

With the aid of SYSWELD heat treatments processes on actual parts is done and it pro-

vide answers to these basic questions:

• Is the selected heat treatment process feasible?

• Is the selected steel feasible?

• Is the selected quenching media suitable?

• Is the process window safe against process tolerances?

• Is the part hard where it should be hard?

• Is there any crack risk occurring during the process?

• Are the obtained distortions acceptable?

• Are the residual compressive stresses high enough and well posi-

tioned?

(Wojciech Sitek, April, 2008), (Harald Porzner, 2008)

Hardenability In Jominy Test 2.4

The aim of jominy test is to ensure that the right hardenability is achieved as already

stated or to have a record of the current hardenability data. So without success being

achieved here in, a good success will not have being achieved to some degree. Below

are two insightful diagrams which we shall discuss more on shortly.

FIGURE 2

Above: quench test of a 0.4wt% carbon steel:

(a) Untempered martensite;


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(b) Ferrite and pearlite. Pearlite, the darker constituent, is a eutectoid mixture of ferrite

and iron carbide.

The Jominy end-quench test measures the hardenability of steel; that is, the ability of

the steel to partially or to completely transform from austenite to some fraction of mar-

tensite at a given depth below the surface when cooled under a given condition from

high temperature. A quench and temper heat treatment uses this phase transformation to

harden steels. Tempering the martensite microstructure imparts a good combination of

strength and toughness to the steel. Without tempering, martensite is hard, but brittle.

To select steel for a component that will be heat treated, it is important to know its har-

denability. Both alloying and microstructure affect the hardenability, allowing the cor-

rect steel and quenching rate to be selected. Prior processing of the steel also affects the

microstructure and should also be considered.

Hardening of steels can be understood by considering that on cooling from high temper-

ature, the austenite phase of the steel can transform to either martensite (Fig. 2a) or a

mixture of ferrite and pearlite (Fig. 2b). The ferrite/pearlite reaction involves diffusion,

which takes time. However, the martensite transformation does not involve diffusion

and essentially is instantaneous. These two reactions are competitive, and martensite is

obtained if the cooling rate is fast enough to avoid the slower formation of ferrite and

pearlite. In alloyed steels, the ferrite/ pearlite reaction is further slowed down, which

allows martensite to be obtained using slower cooling rates. Transformation to another

possible phase (bainite) can be understood in a similar way.

Hardenability describes the capacity of the steel to harden in depth under a given set of

conditions. For example, a steel of a high hardenability can transform to a high fraction

of martensite to depths of several millimetres under relatively slow cooling, such as an

oil quench. By comparison, a steel of low hardenability may only form a high fraction

of martensite to a depth of less than a millimetres, even under quite rapid cooling, such

as water quench.

Steels having high hardenability are required to make large high-strength components,

such as large extruder screws for injection molding of polymers, pistons for rock break-

ers, mine-shaft supports, aircraft undercarriages, as well as for small, high-precision

components, such as die-casting molds, drills and presses for stamping coins. The slow-


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er cooling rates that can be used for high hardenability steels can reduce thermal stresses

and distortion. Steels having low hardenability may be used for smaller components,

such as chisels and shears, or for surface-hardened components, such as gears, where

there is a desire to maintain a ferrite/pearlite microstructure at the core to improve

toughness. The Jominy end-quench test is the standard method to measure the harden-

ability of steels.

(ALNAHYAN, 2008.) (Finnish Standard Assoiciation SFS-EN ISO, 2011.)

Advantages & disadvantages of Jominy Test 2.5

The Jominy end-quench test is developed as a cost- and time-effective way to determine

the hardenability of steel. The test is easy to perform and provides useful information if

you know how to use it. The results of the test allow comparing steels to determine their

equivalent hardenability. However, the hardness values achieved in the test cannot be

used directly for actual parts being oil quenched as it is only a prediction. Furthermore,

is that it is not discriminating when applied to steel of low hardenability. For such

steels, the S-A-C test is considered more reliable. (Herring, 2001.)

Testing Procedure 2.6

FIGURE 3 (A)The Jominy test: Jominy test specimen

The test sample is a 100-mm (4 in.) long by 25.4 mm (1 in.) diameter cylinder (Fig. 3a).

The steel sample is normalized (to eliminate differences in microstructure due to previ-

ous hot working) and then austenitzed usually at a temperature of 800 to 925 ْ C.


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(b) (c) FIGURE 4 The Jominy test:

(b) Jominy test equipment (specimen is inserted at the top, above a jet of water);

(c) Schematic diagram showing the cooling of the Jominy test specimen.

The test sample is quickly transferred to the test fixture (Fig. 4b), which quenches the

steel by spraying a controlled flow of water onto one end of the sample (Fig. 4c). The

cooling rate varies along the length of the sample, from very rapid at the quenched end

where the water strikes the specimen, to slower rates that are equivalent to air cooling at

the other end.

The round specimen is then ground flat along its length on opposite sides to a depth of

at least 0.38 mm to remove decarburized material. Care should be taken that the grind-

ing does not heat the sample, as this can cause tempering, which can soften the steel.

Hardness is measured at intervals from the quenched end, typically at 1.5 mm intervals

for alloy steels and 0.75 mm for carbon steels, beginning as close as possible to the


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quenched end. The hardness decreases with distance from the quenched end. High hard-

ness occurs where high volume fractions of martensite develop. Lower hardness indi-

cates transformation to bainite or ferrite/pearlite microstructures. (Finnish Standard

Assoiciation SFS-EN ISO, 2011.)

FIGURE 5 Schematic of typical hardness profile in a Jominy specimen

FIGURE 6 Schematic continuous cooling transformation (CCT) diagram for an alloy

steel. The cooling curves at the surface and core of a large oil-quenched

component are shown; the surface will be transformed to martensite, but the

core will have a bainitic structure with some martensite.

Measurement of hardness commonly is carried out using a Rockwell or Vickers hard-

ness tester. Conversion charts are available to relate the different hardness scales, but

care should be taken to use the correct charts for steel. Rockwell and Vickers hardness

tests deform the metal differently, and the results are affected by work hardening. The


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hardenability is described by a hardness curve for the steel (Fig. 6), or more commonly

by reference to the hardness value at a particular distance from the quenched end.

(James Marrow, Manchester Materials Science Centre, UMIST, Manchester, UK ,

2001.)

Uses of hardenability values 2.7

Data from the Jominy end-quench test can be used to determine whether particular steel

can be sufficiently hardened in different quenching media, for different section diame-

ters. For example, the cooling rate at a distance of 10 mm (0.390 in.) from the quenched

end is equivalent to the cooling rate at the centre of an oil-quenched 28-mm (1.1 in.)

diameter bar. Full transformation to martensite in the Jominy specimen at this position

indicates that a 28-mm diameter bar can be through hardened; that is, hardened through

its full thickness.

A high hardenability is required for through hardening of large components. This data

can be presented using CCT diagrams (continuous cooling transformation) [6], which

are used to select steels to suit the component size and quenching media. Slower cooling

rates occur at the core of larger components, compared with the faster cooling rate at the

surface. In the example in Fig. 5, the surface will be transformed to martensite, but the

core will have a bainitic structure with some martensite. Slow quenching speeds often

are selected to reduce distortion and residual stress in components. (James Marrow,

Manchester Materials Science Centre, UMIST, Manchester, UK , 2001)

Effects of alloying and microstructure 2.8

FIGURE 7 Schematic of the effect of carbon content (wt%) on the hardness of marten-

site and the combined hardness of martensite and retained austenite, which

can develop at high carbon levels


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FIGURE 8 Schematic of the effect of austenitizing temperature on the hardenability of

steel; higher austenitizing temperatures can coarsen the microstructure

The Jominy end-quench test measures the effects of microstructure, such as grain size,

and alloying on the hardenability of steels. The main alloying elements that affect har-

denability are carbon, a group of elements including Cr, Mn, Mo, Si and Ni, and boron.

(James Marrow, Manchester Materials Science Centre, UMIST, Manchester, UK ,

2001)

2.8.1 Carbon

Carbon controls the hardness of the martensite; increasing carbon content increases the

hardness of steels up to about 0.6wt% carbon. However, at higher carbon levels, the

critical temperature for the formation of martensite is depressed to lower temperatures.

The transformation from austenite to martensite may then be incomplete when the steel

is quenched to room temperature, which leads to retained austenite. This composite mi-

crostructure of martensite and austenite results in a lower steel hardness, although the

hardness of the martensite phase itself is still high.

Carbon also increases the hardenability of steels by retarding the formation of pearlite

and ferrite. Slowing down this reaction encourages the formation of martensite at slower

cooling rates. However, the effect is too small to be commonly used for control of har-

denability. Furthermore, high-carbon steels are prone to distortion and cracking during

heat treatment and can be difficult to machine in the annealed condition before heat

treatment. It is more common to control hardenability using other elements and to use

carbon levels of less than 0.4wt%. (James Marrow, Manchester Materials Science

Centre, UMIST, Manchester, UK , 2001)


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2.8.2 Other alloying elements

Cr, Mo, Mn, Si, Ni and V retard the phase transformation from austenite to ferrite and

pearlite. The most commonly used elements are Cr, Mo and Mn. The retardation is due

to the need for redistribution of the alloying elements during the diffusional phase trans-

formation from austenite to ferrite and pearlite. The solubility of the elements varies

between the different phases, and the interface between the new growing phases cannot

move without diffusion of the slowly moving elements. There are quite complex inter-

actions between the different elements, which also affect the temperatures of the phase

transformation and the resultant microstructure. Alloy steel compositions are, therefore,

sometimes described in terms of a carbon equivalent, which describes the magnitude of

the effect of all of the elements on hardenability. Steels of the same carbon equivalent

have similar hardenability. (James Marrow, Manchester Materials Science Centre,

UMIST, Manchester, UK , 2001.)

2.8.3 Boron

Boron is a very potent alloying element, typically requiring 0.002 to 0.003wt% to have

an equivalent effect as 0.5wt% Mo. The effect of boron is independent of the amount of

boron, provided a sufficient amount is added. The effect of boron is greatest at lower

carbon contents and it typically is used with lower carbon steels.

Boron has a very strong affinity for oxygen and nitrogen, with which it forms com-

pounds. Boron can, therefore, only affect the hardenability of steels if it is in solution.

This requires the addition of "gettering" elements such as aluminum and titanium to

react preferentially with the oxygen and nitrogen in the steel. (James Marrow,

Manchester Materials Science Centre, UMIST, Manchester, UK , 2001)

Grain size 2.9

Increasing the austenite grain size increases the hardenability of steels. The nucleation

of ferrite and pearlite occurs at heterogeneous sites such as the austenite grain bounda-

ries. Increasing the austenite grain size therefore decreases the available nucleation

sites, which retards the rate of the ferrite/pearlite phase transformation. This method of

increasing the hardenability is rarely used because substantial increases in hardenability


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require large austenite grain size, obtained through high austenitizing temperatures. The

resultant microstructure is quite coarse, with reduced toughness and ductility. However,

the austenite grain size can be affected by other stages in the processing of steel, and,

therefore, the hardenability of a steel also depends on the previous stages used in its

production. (James Marrow, Manchester Materials Science Centre, UMIST,

Manchester, UK , 2001)

How to produce the result 2.10

There are several techniques for reviewing process results including both simulated and

practical approaches of jominy test. Some include:

2.10.1 Contourplots

A contour plot is a graphical technique for representing a 3-dimensional surface by plot-

ting constant z slices, called contours, on a 2-dimensional format. That is, given a value

for z, lines are drawn for connecting the (x,y) coordinates where that z value occurs.

The contour plot is an alternative to a 3-D surface plot.

FIGURE 9 This contour plot shows that the surface is symmetric and peaks in the cen-

tre.


17

Other techniques include:

- • Iso-lines and Iso-surfaces

• Vector-Display

• x-y diagrams

• Symbol plots

• Numerical presentation

• Cutting planes

• Animations

(NIST/SEMATECH, 2011.).


18

DESIGN PLAN OF JOMINY TESTING MACHINE 3

Basic concept of the design 3.1

The idea and manner of design is to follow through with the process of meeting up with

the CE standards- Conformité Européenne (Wikipedia, CE mark, 2010) and comple-

menting for the deficits the current machine is having while doing so at a low budget

rate. To achieve this, the use of PRO Engineer CAD programme was employed and the

points explained below where also addressed to complete the design.

3.1.1 Design standardization

By this, we adopt generally accepted uniform procedures, dimensions, materials, or

parts that directly affect the design, more to say, screw holes are unified as much as pos-

sible, the type of material and thickness of metal sheet are unified as often as possible so

as to endeavour to use the same material piece for the whole process. This will ensure

the work piece can be made of lesser tools, less material wastage is achieved, work is

done faster and general overall cost is cheaper.

3.1.2 Why design a new machine & Problems of existing machine

This is because of the need for a more efficient jominy testing machine as the present

machine available is deficient in a number of areas listed below:

- The visibility system for the work in progress is poor, thereby preventing

who is using the machine from having a good view of the work in progress.

- The test piece gripper and support system is not very efficient.

- The used water disposal system is very poor and delays the continuation of a

new test quickly as it goes out slowly.

- The design is not mobile which in some instances is required to move it to a

different location.

- There is not good control of the water supply or the measurement data

achieved from a test process.


19

3.1.3 Possible changes & why this was considered the better design over possible op-

tions

Before the selection of this design choice, two other drawings were made and consid-

ered equally alongside the selected choice. This selection process was based of the cost

of manufacture, complexity and simplicity of the design and operation process, easy

access to the Jominy test piece and the time taken for general operation process. This

was selected because it met more of these requirements and furthermore, looked better

and had some safety devices installed and low cost. It was done with a major aim of

improving pre-existing design and it was accomplished.

10a 10b

FIGURE 10 Diagrams of the New design plan(10a)beside the existing design

plan(10b)showing basic comparisons


20

3.1.4 Features of the new design:

Appearance and style: The new design looks better and the style is more modern

than the pre-existing machine.

Dimensions: The size of the new design is a little similar to the existing one which

follows laboratory standard of convenient working height lengths for a device rising

from the floor. The general size dimensions average 500mm x 500mm x 800mm.

Standardized parts: More of the parts follow standards so it will be easy to manu-

facture if it is considered for large production.

Safety requirements: The machine is designed stylish yet many safety require-

ments are put into consideration such as the wheels which would enable the machine

to be moved without harm from one place to another. It also has a transparent view-

ing top frame installed which will protect the operator or anyone around from get-

ting to closer and at the same time give them the advantage of having a good view

of the entire procedure.


21

FIGURE 11 3D design of the new design plan showing the inner view of the Jominy

testing machine, showing the housing structure.

Water Control and data Analysis: The new design has a larger water control sys-

tem as taps have been installed and the water is allowed to flow in and out at the

will of the operator. Furthermore, the outlet is much larger and the time taken for the

water to flow out after the experiment is much faster than previous design.

FIGURE 12 3D of the inner structural design showing the basic mechanism of the test-

ing machine.

Parts drawing and design: 3.2

This is the first stage using the 3D in which all the various parts to make the machine is

done one after the other. This is a very crucial part of the design as any mistake done

here could go a very long way of altering or jeopardizing the whole project work. Draw-

ings of the various parts are attached at the end of this chapter.

3.2.1 Welding drawing and design:

Upon completion of the various parts drawings, they are categorized based on where

and how they are to be used so with that in mind the parts drawn which are fixed to-


22

gether and function best as a fixed material are welded together. Drawings of the weld-

ed parts are attached at the end of this chapter.

FIGURE 13 3D design showing part of the new testing machine, which the mechanism

will be mounted on top.

3.2.2 2-D Drawings:

Having completed all the stated drawings in the 3-D format, a 2-D format is done. This

is what will be taken to the manufacturing company whom will make the parts for the

actual manufacturing to begin.

3.2.3 Parts with high level of precision:

Amongst the parts to be designed in this project is the support for the Jominy test piece.

This requires a high level of accuracy; as such to prevent errors and defects much cau-

tion should be used when designing this component. There are two parts to be produced

this is to meet up with the two different Jominy tests piece standards. The first is to be

fixed permanently with the other assembled parts while the other is to be made such that

it can be attached or removed to the machine.


23

FIGURE 14 Design of the possible support for the test piece sample.

FIGURE 15 Second possible design for the test piece support which will hold the se-

cond possible type of work piece.


24

3.2.4 Assembly drawing and design:

Assembly drawing and design is the stage which follows afterwards. This does not just

involve putting the parts together but also involves making some adjustments to the

part to make it ready such as making some screw holes shown in all of the parts and

welding drawings. Drawings have been attached for your viewing.

FIGURE 16 3D of the exploded view (right) containing the various components, beside

the final assembled work (left) of the design.


25

MANUFACTURING OF JOMINY TESTING MACHINE POSSIBLE 4

PLAN.

Having made a successful 3D model and 2D drawings of the design, a follow through of

the last chapter can be said to be a manufacturing manual as it involves the making of

all the parts exactly as required which is followed by all the other steps to get the ma-

chine into a ready to use condition. Each paragraph is directly linked to the one before

and after which when done one should have the Jominy end quenching machine. Of

course it does not contain information of how the parts will be cut or details in that re-

gards as it is assumed it will be done by a third party which is specialized in that field.

1.1 Cost &Economic approach to design and manufacture

For any design to be considered successful, the cost of manufacturing and production

should be considered and analysed and managed to be as cheap as possible before actual

design commences. For this design, efforts has been made to ensure it is cheap by

standardizing many of the parts and ensuring same materials could be used where ever

possible to reduce waste and prevent the purchase of more materials. However, the ac-

tual cost for this design cannot be reached at this moment because some of the manufac-

tured parts will be produced by a sister company. But with bill of how much such de-

sign will cost the cost can easily be achieved.

1.1.1 Safety & Maintenance of new manufactured machine

Measures to ensure that the design is very safe were followed. Furthermore, extra fea-

tures such as the visibility screen barrier, wheel for easy mobility which should be

locked when required in a fixed position are some of additional features which make it

safe and give it a unique look which the old design does not have. Furthermore, main-

taining of this design is relatively cheap given there are less fragile or mobile parts; also

the material to be used does not require special maintenance other than that basic kind

for metal works. Some other difference in the maintenance of the new design is pres-

ence of the transparent material used for the visibility frame. These have to be cleaned

before use to maintain a good visibility.


26

CONCLUSION 5

Just as heat treatment process is important in manufacturing processes, Jominy test is as

well important for it has proven to be a most resourceful tool in achieving and determin-

ing the hardness of given metal pieces which must be determined for all metals before

they can actually be used for any given project.

To begin a design work without determining the hardness, toughness, strength or other

technical details of the metal piece will be to make a work blindly or rather as a non-

professional. For these are details which will always be in the specification bill as re-

quired by law before a product can be approved with the CE marking which is the min-

imum conformance mark for any product designed or manufactured.

The proposed designed seems to achieve a higher level of precision however, there are

some hitches which will make it complicated in designing.

The control tap switch we the use of a pressure valve will make the machine advance

but complicated to operate. Furthermore, there are issues with the operation mechanism

that has not yet been resolved and a further look into that concept could be a trilling

experience.

The work piece holder requires a to be held tightly to the support, however, a good an

effective method to tackle this issue was not resolved there by reducing the efficiency of

the design greatly. A possible solution will be to use the currently technology in the

existing machine there by unifying the efficiency in the said section. The new machine

however will still maintain a higher advantage as a result of the enclosure design for-

mats which adds safety, better mobility features, and wider visibility during use and it

serves generally as a better teaching and instructing tool.

An over-roll evaluation, the project can be regarded as a slight improvement if a practi-

cal model was to be designed. To achieve this, the use the structural design of the pro-

posed design and combine the mechanism of the old system in a couple of sections.


27

SOURCES

AG, S. (20th. Janauary 2011a). Heat treatment and characteristics. Referenced 20th.

January 2012address www.saarstahl.de:

http://www.saarstahl.de/arten_der_waermebehandlung.html?&L=1

ALNAHYAN. (15th. Dec 2008). All About Materials Engineering and Me. Referenced

12th. October 2011address http://nayhan.wordpress.com/:

http://nayhan.wordpress.com/pearlite-martensite-austenite-dan-bainite/

Denis S., e. (1984). Heat treatment in metallic materials. Sweden: linkoping.

efunda. (20th. December 2011). Annealing. Referenced 20th. December 2011address

www.efunda.com:

http://www.efunda.com/processes/heat_treat/softening/annealing.cfm

Harald Porzner, P. M. (20th. July 2008). Heat Treatment Simulation Can Help Avoid

Process Problems. Referenced 15th. Nov 2011address http://www.gearsolutions.com:

http://www.gearsolutions.com/article/detail/5819/heat-treatment-simulation-can-help-

avoid-process-problems

Herring, D. H. (10th. october 2001). Jominy Testing: The Practical Side. Referenced

29th. June 2011addresshttp://www.industrialheating.com:

http://www.industrialheating.com/CDA/Archives/c8b7fcf0ddbb7010VgnVCM100000f

932a8c0____

Industrial heating, T. i. (15th. February 2012). Jominy Testing: The Practical Side .

Referenced 15th. February 2012addresswww.industrialheating.com:

http://www.industrialheating.com/Articles/Feature_Article/c8b7fcf0ddbb7010VgnVCM

100000f932a8c0____

James Marrow, Manchester Materials Science Centre, UMIST, Manchester, UK . (7th.

September 2001). Understanding The Jominy End Quench Test . Referenced 10th.

October 2011addresshttp://www.industrialheating.com:

http://www.industrialheating.com/CDA/Archives/22d2fcf0ddbb7010VgnVCM100000f

932a8c0____

NIST/SEMATECH. (7th. June 2011). e-Handbook of Statistical Methods. Referenced

7th. Janurary 2012addresshttp://www.gearsolutions.com:

http://www.itl.nist.gov/div898/handbook/eda/section3/contour.htm

Westmoreland Mechanical Testing & Research, I. (11th. February 2012). The Jominy

End Quench Test ASTMA A255. Referenced 11th. February 2012addresswmtr:

http://www.wmtr.com/Content/Jominy.htm


28

Wikipedia. (10th. July 2010). CE mark. Referenced 16th. August

2011addressWikipedia, the free encyclopedia: http://en.wikipedia.org/wiki/CE_mark

Wikipedia. (30th. January 2012). the free encyclopedia, 2010. Referenced 30th. January

2012addresswww.wikipedia.org: http://en.wikipedia.org/wiki/Heat_treatment

Wojciech Sitek, J. T. (April, 2008). Physical and Numerical Simulation of Materials

Processing. Materials Science Forum (Volumes 575 - 578), 892-897.

Finnish Standard Assoiciation SFS-EN ISO, 6. (15th. Octber 2011.). Steel :

hardenability test by end quenching (Jominy test). Helsinki, Finland: Finnish Standard

Assoiciation SFS-EN ISO , 642 .


Appendix 1

3D MODELS OF THE PROPSOED DESIGN

3D assembly models have being attached such that the designer looks at the end model

and produce the required number of parts to meet the achieve a complete replicate of the

model.

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Pro/ENGINEER wildfire 4.0

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1/1Sheet nro:Sivu numero:

Replays:Korvaa:

Product:Tuote:23:300 surf. finish:

Pint. viimeist:-Approved / Date:Hyväksytty / Pvm:

Treatment:Pinta käs:-James A OrivriDesigner / Date:

Suunnittelija / Pvm:Skaala:Scale:

Yleistoleranssit:General tolerances:

Color:Värisävy:Descript:University of Applied SciencesMaterial:

Materiaali:Nimitys:HAMK Kg6399720.948Total mass:Kokonaismassa:

Identific:Tunnus:

KplPcs

Massa KgMass Kg

Koko:Size:

Tunnus:Identification: Description: Nimitys:Osa

Part

41184.380Base pin1514.99721780.000311639.950421852.500512721.5106119746.16971299214.608811475784.067911475796.0911012565637.877111549883.171visibility_212

Muuttaja: / By:Pvm: / Date: Kuvaus: / Description:Revision:

21.02.2012Drawing file date:EXPLODED_ASSEMBLED_VIEW Drawing filename:BASE_ASSEMBLYModel filename:

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21.02.2012Drawing file date:BASED_SUPPORT_ASSEMBLY Drawing filename:BASE_ASSEMBLYModel filename:

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21.02.2012Drawing file date:VVISIBILITY_FRAME_ASM Drawing filename:BASE_ASSEMBLYModel filename:

jominy test - ammattikorkeakoulut

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